Geochemistry and sedimentary photopigments as proxies to reconstruct past environmental changes in a subtropical reservoir

Autor(es)

Cardoso-Silva, Sheila ^{[1, 2]} ; Soares Silva Mizael, Juliana Oliveira ^[3] ; Frascareli, Daniele ^[3] ; Lopes Figueira, Rubens Cesar ^[1] ; Pompeo, Marcelo ^{[3, 4]} ; Vicente, Eduardo ^[5] ; Moschini-Carlos, Viviane ^[3]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Oceanog Inst, Sao Paulo, SP - Brazil

^[2] Fed Univ Acre UFAC, Ecol & Nat Resources Management Program, Rodovia BR 364, Km 4, BR-69920900 Rio Branco, AC - Brazil

^[3] State Univ Sao Paulo UNESP, Inst Sci & Technol, Environm Sci Program, Sorocaba, SP - Brazil

^[4] Univ Sao Paulo, Biosci Inst, Ecol Dept, Sao Paulo, SP - Brazil

^[5] Univ Valencia, Microbiol & Ecol Dept, Valencia - Spain

• Tipo de documento: Artigo Científico
• Fonte: Environmental Science and Pollution Research; JAN 2022.
• Citações Web of Science: 0

Resumo

Sediment cores were used to establish past environmental impacts associated with eutrophication, erosion and metal contamination in the subtropical Atibainha reservoir (Sao Paulo State, Brazil). We hypothesize that: (1) the levels of nutrients, determined by a spectrophotometric method, reflect the contributions of these elements over time and (2) changes in sedimentation rates, determined by Pb-210 geochronology, and metal flows, determined by ICP-AEOS, are related to anthropic activities. Stratigraphic changes in the analysed variables were used to divide the sediment cores into three intervals, according to PCA and cluster analysis (Euclidian distances, Ward's method). Interval I, composed by the period prior to operation of the reservoir, was influenced by organic matter levels. Interval II, between 1967 and 1993 (PC2: 14.94% of the total variability), a period of minor impacts, was mainly influenced by Mn (eigenvalue of 0.71) and Zn (0.74). Interval III, which included sediment deposited between 1993 and 2015 (PC1: 60.28% of the total variability), was influenced by the highest levels of the pigments lutein (0.86), zeaxanthin (0.90) and fucoxanthin (0.65), together with total nitrogen (0.78) and sedimentation rate (0.91), suggesting changes in the phytoplankton community composition probably associated to the intensification of eutrophication and erosion processes. Despite the limitations of applying paleolimnological techniques in reservoirs and the use of pigments as proxies in regions with higher temperatures, it was observed that the anoxic conditions and the aphotic environment in the hypolimnion acted to preserve pigments associated with the groups Chlorophyta (lutein), Cyanobacteria (zeaxanthin) and Bacillariophyta (fucoxanthin). The isolated analysis of nutrients was not sufficient to make conclusive inferences regarding the eutrophication history, since the levels of TP tended to decrease over time, in contrast to an increase in the levels of TN. Despite intensification of eutrophication and erosion, associated to anthropic activities, no signs of metal contamination were recorded. (AU)

• Processo FAPESP: 19/10845-4 - Qualidade da água de reservatórios paulistas: o peso das evidências
• Beneficiário: Marcelo Luiz Martins Pompêo
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 14/22581-8 - A Diretiva Quadro da Água da Comunidade Européia: aplicações à realidade dos reservatórios brasileiros
• Beneficiário: Marcelo Luiz Martins Pompêo
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 16/15397-1 - Ciclagem de carbono orgânico em reservatórios do brasil e alemanha: influência dos usos do solo e hidrologia
• Beneficiário: Daniele Frascareli
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 16/17266-1 - A Diretiva Quadro da Água da Comunidade Européia: aplicações utilizando o fitoplâncton como discriminador ambiental em reservatórios brasileiros
• Beneficiário: Viviane Moschini Carlos
• Modalidade de apoio: Auxílio à Pesquisa - Regular